The present invention relates generally to a railroad car wheel sensor assembly, and more particularly, to a rail-mounted, wheel-sensing system having a wheel sensor and a mounting bracket therefor.
Today's railroads need to detect the presence of wheels at certain locations on the track. Electrically inductive sensors are often used for this purpose. These sensors, along with their mounting systems, need to be treated as an integrated, matched system this is optimized for freight rail in North America. This means accounting for the effects of heavy haul loads on Class II, III or IV tracks at moderate speeds (10 to 70 miles per hour) and achieving a product cost point which is lower than that of conventional systems.
Rails experience a depression, and almost a shock, when a wheel travels on them. It is therefore necessary that any rail-mounted system for wheel sensors be very rugged and not subject to loosening with vibration over time. In the United States, freight trains generally travel at speeds of up to 70 miles per hour. Presently available wheel sensors are designed for high speed rail travel over 200 miles per hour; however, their mounting brackets are not stout enough to withstand freight traffic conditions.
A further requirement of the railroad industry is that a rail-mounted system be relatively easy and quick to install, particularly with respect to alignment with the rail. Currently available sensors require both vertical and horizontal alignments, which may be difficult to achieve simultaneously. Wheel sensors mounted on these systems are frequently damaged or do not operate correctly either because they are hit by equipment hanging from rail cars or because their brackets are not able to hold them in position over time. Sensors therefore require protection from impacts of dragging equipment with passing cars and resistance to misalignment caused by such impacts and by vibration.
In view of the foregoing, it is desirable to develop a rail-mounted, wheel-sensing system having a wheel sensor which is suitable for U.S. railroad speeds (less than 80 miles per hour).